Dōa Yoshino(Jpn. - 吉乃瞳阿 - "Yoshino Doua") is the first 'official' female Itto-ryu member seen in the series.
Doua is always called a child, although even Rin considers Doa may be the same as as her. She is likely 13-15 years old.
She is very small for her age, and very fast. She carries a heavy foreign sword with ease and often wears a checkered hat in battle, as it is plated in iron on the inside.
Doua is Japanese and was left at the door of an Ainu household as an infant, and therefore raised in Ainu culture until about the age of twelve. Her given name was Kuichiru.
One day, she came across Isaku and his father and their cabin, and continually showed up to hang around. She and Isaku got to know each other, and one day she arrived saying she wanted to leave and travel, and hoped Isaku would go with her. She explained she passed out when her family started giving her the tattoo on her mouth, and later conceded that it was not so much the pain as being marked for life by a tattoo that is not her own which made her so upset.
Isaku and his father come to terms with each other, and Isaku leaves with Doua. Doua asks him to help give her her adult name, and he chooses "Towa”. At some point the pronunciation is changed to "Doua", perhaps to better fit-in in Edo.
They traveled for an indeterminate amount of time, begging for food. When begging didn't work they would sometimes steal, and were often badly beaten. Doua learned to fight back, and over time began attacking and even killing those who would not readily give up their food, money, or belongings, something Isaku did not approve of.